The FT's Hugh Carnegy reports that the proposal goes far beyond Hollande's own manifesto, which calls for a top bracket of 45%, and "seemed to take his own party by surprise".

The timing seems odd too, what with Hollande's trip to London tomorrow. We struggle to see how this announcement will win the support of City-based investors.

Sarkozy has been closing in on Hollande's lead, according to Reuters, halving the gap to 3.5% in just a week. However, Hollande remains far ahead in polls regarding a head to head race between the UMP leader and himself, a distinct possibility in France's two round system. If the move is intended to win over voters, it's perhaps a risky gamble.